Daily Calorie Needs Calculator
Estimate how many calories you should eat per day based on your body, activity, and goal. Results adjust automatically when you change inputs.
Wondering how much calories you should eat per day? This calculator estimates your total daily energy expenditure (TDEE) using the Mifflin–St Jeor equation, then adjusts for your goal — whether you want to lose, maintain, or gain weight. For example, a 30-year-old woman, 165 cm and 65 kg, who exercises 3 times a week typically needs around 2,000 kcal to maintain weight, about 1,500 kcal to lose roughly 0.5 kg per week, or 2,300 kcal to slowly gain lean mass.
Calorie needs are personal and shift with age, body composition, training load, and even sleep quality. A construction worker burns far more than a remote software engineer of the same weight, and recovering from intense exercise can quietly add 200–400 kcal to daily needs. Use this tool as a calibrated starting point: enter your stats once, compare the maintain/cut/bulk numbers, and adjust based on what the scale and mirror show over 2–3 weeks. Re-check every time your weight changes by 3–4 kg.
How it works: We calculate your basal metabolic rate (BMR) with Mifflin–St Jeor, multiply by an activity factor to get TDEE, then apply a goal adjustment (typically ±500 kcal) and split the result into protein, carb, and fat targets.
Do not eat below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision. Sustained intake below these thresholds risks nutrient deficiencies, gallstones, hair loss, and significant metabolic adaptation. This tool is for general informational purposes and is not medical advice. If you have diabetes, thyroid disease, an eating disorder history, kidney disease, are pregnant, or are under 18, consult a registered dietitian or physician before changing your intake. Weight-loss rates above 1% of body weight per week (e.g., >0.7 kg for a 70 kg adult) are associated with greater muscle loss and rebound — slower is almost always better long-term.
How Many Calories Should You Eat Per Day?
Your daily calorie target depends on size, activity, and goal — not a one-size-fits-all 2,000 kcal label. Below is the math, the lookup tables, and the practical adjustments that actually work.
Typical daily calorie needs by sex, age, and activity (kcal/day, maintenance)
| Group | Sedentary | Moderately active | Very active |
|---|---|---|---|
| Women 19–30 | 1,800–2,000 | 2,000–2,200 | 2,400 |
| Women 31–50 | 1,800 | 2,000 | 2,200 |
| Women 51+ | 1,600 | 1,800 | 2,000–2,200 |
| Men 19–30 | 2,400–2,600 | 2,600–2,800 | 3,000 |
| Men 31–50 | 2,200–2,400 | 2,400–2,600 | 2,800–3,000 |
| Men 51+ | 2,000–2,200 | 2,200–2,400 | 2,400–2,800 |
Activity multipliers and what they look like in daily life
| Multiplier | Label | Weekly exercise | Daily steps | Example job |
|---|---|---|---|---|
| 1.20 | Sedentary | None | <5,000 | Remote worker, mostly seated |
| 1.375 | Lightly active | 1–3 sessions, light | 5,000–8,000 | Teacher, retail (part-time) |
| 1.55 | Moderately active | 3–5 sessions, moderate | 8,000–12,000 | Nurse, server, parent of toddlers |
| 1.725 | Very active | 6–7 sessions, hard | 12,000–16,000 | Trainer, landscaper |
| 1.90 | Extremely active | 2-a-days or hard labor + training | >16,000 | Construction + evening training |
Goal adjustment cheatsheet (kcal/day off TDEE)
| Goal | Adjustment | Expected weekly change | Best for |
|---|---|---|---|
| Aggressive fat loss | -750 kcal | -0.7 kg | Short cuts, higher body fat |
| Steady fat loss | -500 kcal | -0.45 kg | Most people, 8–16 weeks |
| Mild fat loss | -250 kcal | -0.25 kg | Lean dieters, recomp |
| Maintenance | 0 | 0 | Reverse diets, performance |
| Lean bulk | +300 kcal | +0.25 kg | Minimizing fat gain |
| Fast bulk | +500 kcal | +0.45 kg | Hardgainers, off-season |
Why a Single Number Like 2,000 kcal Is Misleading
The FDA's 2,000 kcal label is a rounded average across the U.S. population — not a personal prescription. A 5'2" sedentary woman of 55 kg may maintain on just 1,500 kcal, while a 6'1" active man of 90 kg can eat 3,200 kcal and lose weight. The Mifflin–St Jeor equation closes that gap by using your specific weight, height, age, and sex, and is validated within roughly ±10% for most adults. As a rule of thumb: every additional 10 kg of body weight adds ~100 kcal/day, and every activity tier adds ~15–20% on top of BMR.
How Activity Level Changes Everything
Activity multipliers reward both formal exercise AND non-exercise movement (NEAT). Someone who lifts 4x/week but sits the rest of the day is closer to 'lightly active' (×1.375) than 'very active' (×1.725). A reliable test: if your watch reports under 8,000 steps and you train 3x/week, you're moderately active at best. Be conservative — research consistently shows people overestimate activity by one tier, which inflates targets by 250–400 kcal/day and stalls fat loss. When in doubt, pick the lower tier for 2 weeks and adjust upward only if weight stays flat.
Understanding the Calculator Inputs (and What Happens at the Edges)
Weight is the biggest single driver — it appears in BMR with a ×10 multiplier. Height adds ×6.25, and age subtracts ×5 per year. Selecting 'male' adds 166 kcal versus 'female' due to typical lean-mass differences. The calculator floors targets at 1,200 kcal for women and 1,500 kcal for men, because cutting below that risks micronutrient deficiency and metabolic adaptation. If you enter 0 or extreme values, the tool clamps to the realistic range (30–250 kg, 120–230 cm). Switching weight from kg to lb only changes how you type the number — internal math always converts to kilograms.
Protein, Carbs, and Fat: How We Split Your Target
Calories drive weight change; macros drive what you keep or lose. The calculator sets protein at 1.8 g/kg for maintenance and gain, and 2.0 g/kg during a cut to preserve muscle. Fat is fixed at 27% of calories (roughly 0.8–1.0 g/kg) to support hormones — going below 20% for extended periods is linked to lower testosterone and menstrual disruption. The remainder fills as carbs, which fuel training intensity. A 70 kg lifter cutting at 1,800 kcal would land near 140 g protein, 55 g fat, and 155 g carbs.
Common Mistakes That Make Calorie Counts Wrong
Five mistakes account for most plateaus: (1) eyeballing oils — one tablespoon is 120 kcal and easy to miss; (2) weighing food cooked instead of raw, which can underreport rice and pasta by 60%; (3) cheat meals adding 1,500+ kcal and erasing a week of deficit; (4) liquid calories from lattes, juice, and alcohol; (5) untracked weekend eating, where intake jumps 500 kcal/day. Track meticulously for 2 weeks to calibrate, then loosen. If the scale doesn't move in 14 days despite hitting your number, your intake is likely 200–400 kcal higher than logged.
How Often Should You Recalculate?
Recalculate any time your weight changes by 3–4 kg, your activity level shifts (new job, injury, season), or you cross a decade in age. During a cut, expect TDEE to drop 10–15% beyond what the formula predicts, due to adaptive thermogenesis and reduced NEAT — this is why long diets stall. The fix isn't more deficit; it's a 1–2 week diet break at maintenance every 8–12 weeks. During a bulk, recompute every 2–3 kg gained: a heavier you needs more food to keep growing.
Special Situations: Pregnancy, Older Adults, and Athletes
This calculator is designed for healthy non-pregnant adults aged 14–90. Pregnant women need roughly +340 kcal/day in the second trimester and +450 kcal in the third; lactating women need ~+500 kcal — none of which this tool models. Adults over 65 should keep protein at 1.6–2.0 g/kg to combat sarcopenia, even if calories drop. Competitive athletes training 15+ hours/week often need an activity factor above 1.9 and may add 300–800 kcal on hard training days using a 'flexible' approach rather than a fixed daily number.
How This Calculator Works: Methodology & Parameter Explanations
Core formula:
BMR = 10·W + 6.25·H − 5·A + s (s = +5 male, −161 female); TDEE = BMR × activity factor; Target = TDEE + goal adjustmentwhere:
W— Body weight (kg)H— Height (cm)A— Age (years)s— Sex constant (kcal)
How to apply: BMR is just resting cost. Multiply by an activity factor (1.2–1.9) to capture daily movement and exercise, then add a goal adjustment in kcal/day: −500 for steady fat loss, 0 for maintenance, +300 for lean gain. Compare the result against your actual weight trend after 14 days and recalibrate.
Worked example: Take a 35-year-old woman weighing 68 kg at 168 cm, moderately active, who wants to lose weight. BMR = 10·68 + 6.25·168 − 5·35 − 161 = 680 + 1,050 − 175 − 161 = 1,394 kcal. TDEE = 1,394 × 1.55 = 2,161 kcal. With a −500 kcal cut, her daily target lands near 1,660 kcal, projecting ~0.45 kg/week of fat loss with protein at 1.8 g/kg = 122 g.
Alternative formulas
Harris–Benedict (revised 1984): Men: BMR = 88.36 + 13.40·W + 4.80·H − 5.68·A; Women: BMR = 447.59 + 9.25·W + 3.10·H − 4.33·A
When to use: Older equation; tends to overestimate by 5–15% in overweight adults. Use only when comparing legacy data.
Katch–McArdle: BMR = 370 + 21.6·LBM (LBM in kg)
When to use: Best for lean, well-trained athletes who know their body-fat percentage from DEXA or hydrostatic testing.
Cunningham: BMR = 500 + 22·LBM
When to use: Used by sports dietitians for elite athletes with very high lean mass; assumes accurate LBM measurement.
Parameter explanations
| Input | Unit | What it means | Impact on results |
|---|---|---|---|
| Age | years | Chronological age in years; older adults have lower BMR due to gradual lean-mass loss. | Each additional year subtracts 5 kcal from BMR — small per year but ~50 kcal/decade compounds. |
| Biological sex | — | Male/female toggle that sets the constant in Mifflin–St Jeor (+5 or −161), reflecting average differences in lean mass. | Switching male→female reduces BMR by 166 kcal/day at the same weight and height. |
| Weight | kg (canonical) or lb | Current body weight. Pounds are auto-converted to kilograms internally (1 lb = 0.4536 kg). | Largest single driver: each additional 10 kg raises BMR by 100 kcal and TDEE by ~155 kcal at moderate activity. |
| Height | cm (canonical) or in | Standing height; inches are auto-converted to centimeters (1 in = 2.54 cm). | Each additional 10 cm adds 62.5 kcal to BMR — meaningful but smaller than weight. |
| Activity level | — | Categorical multiplier capturing both exercise and non-exercise daily movement. | Moving from sedentary (×1.2) to very active (×1.725) increases TDEE by ~44% — often 600–900 kcal/day. |
| Goal | kcal/day adjustment | Whether you want to lose, maintain, or gain, and how aggressively. | Shifts target by −750 to +500 kcal/day. A 500 kcal deficit equals roughly 3,500 kcal/week ≈ 0.45 kg of fat. |
| Average sleep per night | hours | Typical nightly sleep duration. Doesn't change BMR math but drives personalized insights. | Under 6.5 hours flags a warning about elevated hunger hormones and adds 200–400 kcal of perceived appetite. |
Assumptions
You are a non-pregnant, non-lactating adult aged 14–90 without metabolic disease.
Mifflin–St Jeor accuracy is ±10% for most adults — The equation was validated on 498 adults in 1990 and remains the ADA-preferred formula. It tends to slightly overestimate in very lean individuals and underestimate in those with high muscle mass.
Activity multipliers include both exercise and NEAT — The 1.2–1.9 range covers basal movement plus exercise. Don't double-count by adding workout calories on top of an already 'moderately active' multiplier.
The example numbers in the keyword are defaults only — Common figures like '2,000 kcal/day' are population averages, not personal targets. The tool computes a target from your specific inputs, and any sample numbers shown are illustrative.
A 500 kcal/day deficit produces roughly 0.45 kg/week of weight loss, assuming protein and training preserve muscle.
Macro split uses protein 1.8–2.0 g/kg, fat ~27% of calories, and carbs filling the remainder.
How to use this calculator
- Enter your stats honestly — Use current weight (not goal weight) and pick the activity tier matching your last 2 weeks, not your best week ever.
- Compare maintain vs cut vs bulk — Toggle the goal selector to see how your target shifts. This shows the actual cost of each goal in kcal/day terms.
- Track for 14 days at the target — Weigh yourself daily, average the week, and only judge progress after two full weeks — short-term swings are mostly water.
- Adjust by 100–200 kcal if stalled — If weight didn't move (cut) or only moved water (bulk), nudge calories by 100–200 kcal/day, not 500. Big swings cause big problems.
- Recalculate every 3–4 kg of change — Your TDEE drifts as your body changes. Re-enter new weight and reset the target rather than guessing.